Now that the U.S. EPA’s Lead and Copper Rule has been finalized, planning is underway in communities across the country to replace the estimated 9 million service lines made of lead or galvanized steel. This should reduce the amount of lead in the nation’s public water systems, but can it introduce another potential hazard – Legionella?
What is Legionella?
Legionella is a genus of pathogenic gram-negative bacteria. Legionellosis, the infection caused by Legionella, includes a pneumonia-like condition called Legionnaires’ disease and a flu-like illness referred to as Pontiac fever. Most healthy individuals exposed to Legionella recover quickly. Many never develop symptoms at all. However, older adults, people with compromised immune systems, and those suffering from chronic diseases, are at increased risk of infection. These infections can be severe and even fatal.
How Exposure to Legionella Happens
Legionellosis is typically contracted by inhaling water droplets contaminated with Legionella bacteria. This is one reason most cases can be tracked back to devices or architectural features that aerosolize water. Hot tubs, showers, decorative fountains, and cooling towers are frequent sources.
It is also possible, though much less common, to get sick by aspirating contaminated drinking water. Aspiration occurs when liquids accidentally enter the lungs, which can happen if water "goes down the wrong pipe" during drinking. It is not believed that one can get sick from simply drinking Legionella-contaminated water.
Why Replacing Lead Pipes May Increase Legionella Hazards
To understand the connection between lead pipes and Legionella, we need to start by looking at why these pipes are a natural breeding ground for the bacteria and why replacing them may actually increase the hazards, at least temporarily.
Legionella is a naturally occurring bacteria in surface waters, such as lakes and ponds, which are often used as drinking water sources. Conventional water treatment methods, including filtration and disinfection, are considered generally effective at reducing or eliminating Legionella from drinking water. However, if improperly implemented or maintained, Legionella can slip through into the distribution system. .png?width=365&height=365&name=sampling%20(3).png)
The bacteria naturally present in water pipes secrete a slimy substance that can build up on the walls of pipes. This “biofilm” creates a stable environment for microorganisms to colonize. Now that the Legionella has found its way into the water distribution system, it finds a new home in the biofilm lining the pipes. Older pipes, such as the lead service lines, are more likely to have thicker biofilms with more bacterial growth. It’s a compounding problem. Since these biofilms are corrosive, the uneven surfaces of older pipes become even more hospitable to bacterial colonization. It’s the microbial world’s version of terraforming.
Thankfully, routine use of these lines won’t normally dislodge these bacterial colonies, or we’d have more outbreaks of Legionnaires’ disease on our hands. However, these colonies are fragile enough to be dislodged into the water stream by activity, such as changes in water pressure.
As everyone who’s ever had their water turned off during construction or routine maintenance knows, the water that comes out of the faucet afterwards can, at first, be a disturbing shade of brown or black. The color is usually caused by loosened corrosion and sediment, but it can also contain bacteria from disturbed biofilms. Thus, construction activities, in the short-term, can increase the risk of Legionella exposure—a risk that can be mitigated through the right testing and response.
How to Protect Your Customers
The CDC has published guidance on precautions to take when reopening a building after a prolonged period of disuse. The hazards they focus on, i.e., changes in water pressure that can dislodge bacterial colonies, are similar those that happen during construction. Therefore, many of their recommendations, such as specific instructions for flushing water systems, are suitable to projects involving the replacement of lead pipes.
Facilities impacted by the replacement of lead service pipes may also want to take time to review their water management plan and consider testing for Legionella during construction activities, in addition to any routine testing. This is especially important if your building occupants fall into the high-risk category. The Centers for Medicare and Medicaid Services (CMS) requires healthcare facilities that receive funding to have a working water management plan.
Have questions?
The Pace® Building Sciences team offers services for testing Legionella, lead and many other potentially hazardous contaminants in drinking water. Our team can also work with you through your water management planning process or review your current water management plans. Visit our website or reach out to us to learn more.
